1. Field
One embodiment of the invention relates to improvement of a recording method for a single-sided, multi-layer information recording medium. More particularly, one embodiment of the invention relates to a method of determining an area range used in recording for a single-sided, multi-layer recording type optical disc (for at least two neighboring layers of a disc having three or more layers on one side), a finalization processing method, and a recording or playback apparatus using this disc.
2. Description of the Related Art
As media for large-capacity information recording, optical discs represented by digital versatile discs (DVDs) have been prevalently used. In recent years, a demand has arisen for long-term video recording at a high bit rate along with broadcasting with high image quality. As one of approaches to meet such demand, multi-recording layers are adopted. Especially, a demand for single-sided, multi-layer discs which need not be turned over in actual use is high. As typical examples of single-sided, multi-layer information recording media, DVD+R/DL, DVD-R/DL, and the like are known.
As DVD+R and DVD-R media, those for single layer recording (to be abbreviated as SL hereinafter) and those for dual layer recording (to be abbreviated as DL hereinafter) are available (a disc which has one recording layer on each of both the sides of the disc, and cannot perform recording or playback for the two layers on the two sides from one side of the disc is handled as SL). In recording of DL media, normally, layer 0 as the 0th layer (first recording layer L0) undergoes recording from the inner periphery toward the outer periphery of a medium to a position in front of a (pre-set, fixed) middle area. Then, the layer is switched, and layer 1 as the 1st layer (second recording layer L1) undergoes recording from the outer periphery toward the inner periphery.
In disc media such as DVDs and the like, write errors tend to occur more frequently as the write position moves from the inner periphery toward the outer periphery of a medium (surface run-out of a rotating disc tends to increase at the outer periphery side more than that at the inner periphery side). As one of methods of avoiding recording reliability drop due to frequent occurrence of errors, a method which inhibits use of the outer periphery side of a disc is known. More specifically, for example, as shown in FIG. 3, the switching position of the recording layer from layer 0 (L0 layer) to layer 1 (L1 layer) is shifted to a shifted middle area which is nearer to the inner periphery side than the fixed middle area on the outer periphery side, and an area on the outer periphery side of the shifted middle area is not used in recording. A technique itself for setting such shifted middle area is known (see Jpn. Pat. Appln. KOKAI Publication No. 2004-310972).
In Jpn. Pat. Appln. KOKAI Publication No. 2004-310972, the shifted middle area is set according to the user data size to be recorded. However, the aforementioned frequent occurrence of errors is different for respective discs, and also changes depending on a disc loading state to a drive to be used. Hence, in consideration of frequent occurrence of errors (or recording reliability drop), the method of setting the shifted middle area based on the user data size does not suffice.
In DL media, different time periods are to be taken for finalization from a state in which recording has been done up to the middle of the 1st layer (second recording layer L1=layer 1), and that from a state in which recording has been done up to the middle of the 0th layer (first recording layer L0=layer 0). That is, in the state shown in FIG. 2, the application side or drive writes data (lead-out or all'0 stuffing) to set the same recorded states of 0th layer L0 and 1st layer L1, and pre-processing for finalization takes much time.